Pituitary Adenoma Extended to the Basilar Sinus: Lessons from Anatomical and Radiological Study（An Experimental Research）

Pituitary Adenoma Extended to the Basilar Sinus: Lessons from Anatomical and Radiological Study（An Experimental Research） | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Pituitary Adenoma Extended to the Basilar Sinus: Lessons from Anatomical and Radiological Study（An Experimental Research） Xiao Wu+, Li Min Xiao, HaoYang Peng, Shi Zhou Xing, Peng Wang, and 10 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6634932/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 03 Oct, 2025 Read the published version in Neurosurgical Review → Version 1 posted 13 You are reading this latest preprint version Abstract Purpose Pituitary adenoma (PA) with basilar sinus extension has been neglected in previous literature. In this study, 47 cases of such a subset of PAs were introduced, and the surgery-related anatomy and strategies were discussed. Methods The medical records of patients with basilar sinus extension were analyzed retrospectively. Four human head specimens were used for epoxy sheet plastination, and five were used for endoscopic endonasal dissection. Results The connection between the cavernous sinus (CS) and the basilar sinus is located in the superomedial space of the gulfar segment abducens nerve and beneath the petrosphenoidal ligament. The characteristic manifestation on enhanced sagittal MR images is the “triangle” sign, which means that the high signal in the basilar sinus disappears and is replaced by triangular-like tumor protrusions without destruction of the clivus or dorsum sellae. The most common symptom was endocrine dysfunction (17 patients; 36.2%), with 88.2% of patients experiencing remission postoperatively. According to the dataset, 83% of patients achieved total resection through the endoscopic endonasal approach. Abducens nerve palsy (3 patients, 6.4%) were the most common postoperative complications, but two patients were alleviated during postoperative follow-up. Conclusion The basilar sinus can serve as a potential breakthrough path through the CS compartments for PA invasion. With a clear anatomical understanding of the invasion corridor for this subset of PAs and corresponding surgical techniques, PAs can be safely removed without increasing surgical risk. basilar sinus epoxy sheet plastination pituitary adenoma cavernous sinus endoscopic endonasal approach Figures Figure 1 Figure 2 Figure 3 Figure 4 Highlights 1.Special attention should be given to the "triangle” sign in preoperative sagittal imaging, especially for Grade Knosp4 PAs. 2.The basilar sinus can serve as a potential breakthrough route through the cavernous sinus compartments for PA invasion. Introduction Treatment strategies for pituitary adenoma (PA) need to consider many aspects, which promotes the development of clinical and anatomical research. Previous studies have confirmed that PAs can invade surrounding structures through various anatomical weak points, and these types of tumors are often referred to as invasive PAs by scholars.1 The variety of invasive modalities makes surgical treatment difficult, even for experienced skull base surgeons. One of the most challenging types is PA with cavernous sinus (CS) invasion, which is also the focus of numerous clinical reports. [ 1 – 6 ] However, it is still believed that a small subset of PAs can further extend to other locations through the CS, such as the paraclinoid and parapeduncular spaces, which would cause certain challenges to the total resection of tumors. [ 4 , 7 ] As Kawase et al. [ 8 ] and Xu et al. [ 1 ] showed, the meningeal structure within the CS has several weak points, providing a potential route for tumor extension. In contrast to the looseness and thinness of the medial wall of the CS or oculomotor cistern, the basilar sinus, as a normal venous drainage channel, can also become a weak point in the CS, leading to further extension of the PAs. Nevertheless, PAs with basilar sinus extension may be overlooked in many patients with coexisting predominant CS, clivus and suprasellar extension, leading to intraoperative residual tumor and postoperative recurrence. Whether this subset of PAs has characteristic imaging manifestations is an issue that deserves further exploration. We previously conducted in-depth research on PAs with multiple corridor invasion, such as the CS, clivus, and diaphragma sellae. [ 2 , 6 , 9 – 12 ] The aim of the present study was to highlight the basilar sinus corridor and related surgical strategies for PA extension through anatomical research and clinical case studies, which have not been described previously. This particular subset of PAs has implications for the total resection rate, symptom relief, and postoperative recurrence for endoscopic endonasal surgery. Method Anatomical Study This study was authorized by the Ethics Committee of e First Affiliated Hospital of Nanchang University. Four cadaver head specimens were used for epoxy sheet plastination to elaborate the CS-basilar sinus corridor in axial and sagittal sections. Five colored silicon–injected human head specimens were used for endoscopic endonasal dissection. The anatomical process of endoscopic endonasal approach (EEA) with a 4 mm diameter × 18 cm length endoscope (Karl Storz, 0° and 30°). The bilateral endoscopic endonasal transpterygoid and transclival approaches were used to expose the basilar sinus and lateral compartment of the CS to simulate the operation process. Patient Selection and Analyses The clinical and radiological database was examined to identify PA patients who received EEA treatment from July 2017 to June 2023. Among these patients, we screened PAs with basilar sinus extension that met our inclusion criteria. The inclusion criteria were as follows: 1) basilar sinus extension without bone destruction in the dorsum sellae based on preoperative imaging and intraoperative evaluation; 2) complete preoperative and postoperative imaging data and postoperative follow-up data; and 3) postoperative pathology confirming that the tumor was PA. Preoperative clinical data, including sex, age, clinical manifestations, and endocrine and ophthalmic examination results, were obtained from medical records. All patients underwent routine T1- and T2-weighted imaging and T1-weighted 3D MP-RAGE sequencing before and after the operation (Siemens, Erlangen, Germany). The Knosp grade and subclassification were used to evaluate cavernous sinus invasion. [ 2 , 3 ] Postoperative evaluation The postoperative evaluation included reexamination imaging, histopathological findings, ophthalmic examination results and complications. The time from resection to the last call was defined as the follow-up time in this study. To narrow the differences among evaluators, the extent of tumor resection was determined by an individual neuroradiologist and experienced neurosurgeons through preoperative and postoperative enhanced MRI. The resection range was determined by postoperative MRI. Gross total resection (GTR) was defined as no residual tumor. Subtotal resection(STR)was defined as a resection range ≥ 80%. Partial resection (PR) was defined as a resection range < 80%. Endocrine remission was evaluated at 3 months postoperatively according to the guidelines from the latest consensus. [ 13 – 15 ] For prolactin (PRL)-secreting adenomas, serum PRL < 20 ng/mL in female patients or, < 15 ng/mL in male patients; for adrenocorticotropic hormone (ACTH)-secreting adenomas, a serum cortisol nadir of < 2 mg/dL or normal 24-hour urinary free cortisol test at 3 months; and for growth hormone (GH)-secreting tumors, normalization of serum insulin-like growth factor-1 level (IGF-1), basal serum GH < 2.5 ng/mL, or an oral glucose tolerance test of 0.4 ng/mL. Results Anatomic Findings The basilar sinus includes lateral interconnecting channels with the CS and connects the vertebral venous plexus downward and the inferior petrosal sinus laterally. The connection between the CS and the basilar sinus is located in the interdural space on the dorsal side of the clivus, behind the posterior genu of the CS segment of the ICA. In front is the periosteum layer of the clivus, and behind is the meningeal layer of the brainstem. It can also be considered the superensomedial space of the gulfar segment abducens nerve and beneath the petrosphenoidal ligament, which contains the meningohypophyseal trunk and its branches. (Fig. 1 , 2 ) Patient Demographics A total of 881 patients were diagnosed with PA and underwent surgery during the study period and had pre- and postoperative images available for review. A total of 47 patients exhibited basilar sinus extension—30 females and 17 males—with an average age of 45.5 years. Eight patients with a history of previous surgery. The predominant presenting symptom observed was endocrine dysfunction (17 patients, 36.2%), including Cushing disease in 3 (6.4%) cases, prolactinomas in 2 (4.2%) cases, and acromegaly in 12 (25.5%) cases. Among these patients, prolactinomas choose surgery because of drug intolerance and obvious adverse reactions. Other symptoms included visual disturbance (16 patients, 34%), headache (12 patients, 25.5%) and cranial nerve palsy(3 patient, 6.4%). The overall maximum diameter could be divided into 16 (34%) case of macroadenomas and 31 (66%) case of giant adenomas. The mean tumor volume was 33.8cm³. Based on the degree of CS invasion, 11 (23.4%) patients had Knosp grade 3 tumors, 10 (21.3%) had grade 4A tumors, 4 (8.5%) had grade 4B tumors, and 22 (46.8%) had grade 4AB tumors. There were 33 (70.2%) patients with Ki-67 ≥ 3 and 14 (29.8%) patients with Ki-67 < 3. The total follow-up time ranged from 8 to 79 months, with an average of 41.6 months. (Table 1 ). Table 1 Clinical characteristics of 47 PAs with basilar sinus extension Variable Value No. of patients 47 Age in yrs (range) 45.5 (10–69) Sex Female (%) 30 (63.8) Male (%) 17 (36.2) Tumor subtypes 3 (%) 11 (23.4) 4A (%) 10 (21.3) 4B (%) 4 (8.5) 4AB (%) 22 (46.8) Preop Sxs Visual disturbance (%) 16 (34.0) Endocrine dysfunction syndrome (%) 17 (36.2) Headache (%) 12 (25.5) CN palsy CN III palsy (%) 2 (4.2) CN VI palsy (%) 1 (2.1) Incidental finding (%) 3 (6.4) Tumor size Macroadenomas (%) 16 (34.0) Giant PAs (%) 31 (66.0) Tumor volume 33.8cm³ NFA (%) 30 (63.8) FA (%) 17 (36.2) Cushing disease (%) 3 (6.4) Prolactinomas (%) 2 (4.2) Acromegaly (%) 12 (25.5) Previous surgery (%) 8 (17.0) Ki-67 ≥3 (%) 33 (70.2) <3 (%) 14 (29.8) Mean follow-up in mos (range) 41.6 (8–79) FA = functional adenoma; NFA = nonfunctional adenoma; Sxs = symptoms. Subtypes of KG4PAs were evaluated according to the latest report. 2 Imaging characteristics Radiographically, this tumor has a characteristic presentation and usually appears as a Knosp grade 4 PA with obvious extension in the lateral compartment of the CS. The PA extension is limited by the anterior periosteum layer in the clivus and posterior meningeal layer, forming a characteristic triangular structure(Figure 1 E, 3 D and 4 A). In addition, the high signal density of the basilar sinus was obliteration, and the “triangle” sign reached the lower clivus on T1-weighted imaging with gadolinium contrast enhancement in the sagittal section; however, there was no bony destruction of the clivus or dorsum sellae on the CT bone window. In detail, the three edges of the triangle symbol represent the clival surface, the posterior boundary of the tumor, and the connecting line between the superior surface of the dorsum sellae and the posterior boundary of the tumor. Surgical techniques The surgical procedures were performed under the protection of neuronavigation, intraoperative electrophysiological monitoring and Doppler measurements. Most of the patients were Knosp grade 4 with lateral compartment invasion of the CS, which was preoperatively judged via MRI and reaffirmed intraoperatively. As a result, a transpterygoid approach on the tumor side was needed to expose the lateral compartment of the CS and paraclival internal carotid artery (ICA) as the proximal control point. The surgical strategies and details for Knosp4 PAs have been described in our previous publications. [ 2 , 6 ] A special feature of this type of PA surgery is that the tumor in the CS is usually removed first until the area connecting to the basilar sinus is reached. To aid in the mobilization of the ICA, the meningohypophyseal trunk or inferior hypophyseal artery was cautiously coagulated and transected. PA with basilar sinus extension hiding behind the clivus is considered a blind spot in endoscopic endonasal surgery. Therefore, for patients with “triangle” signs on preoperative imaging, the transclival approach was used to remove a portion of the bone in the clivus and the dorsum sellae, especially at the midline and the sphenoid occipital junction. Due to the basilar sinus within the interdural space, the tumor can be found by opening the periosteal layer in the clivus. In these patients, there was less bleeding from the basilar sinus, and the tumor was relatively well identified. With the cooperation of neuronavigation and angle endoscopy, the tumor can be completely removed. At this point, bleeding from the basilar sinus increased, thus requiring compression hemostasis with fluid gelatin. The probability of intraoperative cerebrospinal fluid(CSF) leakage was low, owing to protection of the meningeal layer, and the skull base is reconstructed sequentially using the traditional method of autologous fat, T-frame, fibrin glue and nasal septum mucosal flap. Surgical outcomes In this series, a comprehensive analysis revealed that 39 patients (83%) benefited from GTR, while the remaining 6 patients (12.8%) underwent STR and 2 patients (4.2%) underwent PR. During the last follow-up, the preoperative symptom of endocrine dysfunction improved in 15 patients (88.2%) to varying degrees. Other symptoms included visual disturbance, headache and cranial nerve palsy improved in 12 patients (75%), 8 patients (67.7%) and 2 patients (67.7%) respectively. After surgery, 3 patients (6.4%) had transient cranial nerve palsy, 1 patient (2.1%) had permanent cranial nerve palsy, and another 1 patient (2.1%) had CSF leakage. No patient experienced lethal ICA injury. (Table 2 ). Table 2 Surgical results and postoperative complications in 47 patients Variable Total (47) NFAs (30) FAs (17) Extent of resection GTR (%) 39 (83.0) 24 (80.0) 15 (88.2) STR (%) 6 (12.8) 4 (13.3) 2 (11.8) PTR (%) 2 (4.2) 2(6.7) 0 Resolution of preop Sxs Visual disturbance (%) 16 (34.0) 11 (36.7) 5 (29.4) No change (%) 4 (25.0) 3 (27.3) 1 (20) Improved (%) 12 (75.0) 8 (72.7) 4 (80) Headache (%) 12 (25.5) 8 (26.7) 4 (23.5) No change (%) 4 (33.3) 2 (25.0) 2 (50.0) Improved (%) 8 (67.7) 6 (75.0) 2 (50.0) CN palsy (%) 3 (6.4) 2 (6.7) 1 (5.9) No change (%) 1 (33.3) 0 1 (100) Improved (%) 2 (67.7) 2 (100) 0 Endocrine remission Yes (%) 15 (88.2) 0 15 (88.2) No (%) 2 (11.8) 0 2 (11.8) Postop complications Transient CN palsy (%) 3 (6.4) 2 (6.6) 1 (5.9) CN III 1 (2.1) 1 (3.3) 0 CN VI 2 (4.3) 1 (3.3) 1 (5.9) Permanent CN palsy (%) 1 (2.1) 1 (3.3) 0 CN III 0 0 0 CN VI 1 (2.1) 1 (3.3) 0 CSF leakage (%) 1 (2.1) 0 1(5.9) ICA injury (%) 0 0 0 Illustrative Cases Patient 1 A 31-year-old female with PA was admitted to the hospital for tumor recurrence 3 years after the first endoscopic endonasal surgery. Ophthalmic examination revealed that the patient’s binocular vision decreased. On the MRI of the first surgery, the patient had a normal pituitary on the right side and a tumor with CS invasion on the left side. The patient underwent EEA to remove intrasellar and CS tumors, but the basilar sinus corridor was ignored because it was not recognized at the time. Multiple postoperative follow-up visits revealed that the tumor in the basilar sinus gradually increased, and radiotherapy or reoperation was recommended. However, the patient chose to continue the observation because of her lack of symptoms and fertility requirements. Three years later, MRI reexamination revealed that the “triangle” sign had reached the middle clivus, which was approximately 3.2 × 1.8 × 2.3 cm in size. During the operation, we completely removed the tumor through the transclival approach. Postoperative imaging demonstrated that the tumor was completely removed, and there were no significant complications. (Fig. 3 ) Patient 2 A 25-year-old female with headache and dizziness for 1 month. She had two previous PA surgical histories through the EEA due to acromegaly and postoperative pathological confirmation of growth hormone adenoma. Ophthalmic examination showed no obvious decline in vision or visual field. Preoperative sagittal MRI showed that the “triangle” sign had reached the inferior clivus. Axial MR image showing an irregular density shadow in the right CS and an incased ICA, measuring approximately 3.5 × 1.6 × 1.8 cm. Preoperative CT revealed intact bone on the surface of the clivus, with a posterior space-occupying lesion connecting the CS. The patient underwent endoscopic endonasal surgery. After the transpterygoid approach was used to expose the paraclival ICA and the bony surface of the clivus and anterior wall of the CS were removed, the PAs were completely exposed. At this time, the PAs in the CS were removed first, after which the tumor was exposed by opening the periosteal layer on the clival surface. There was no CSF leakage after the tumor within the basilar sinus was completely removed. The patient's left eyeball abduction was limited, and her pituitary function decreased postoperatively. Through rehabilitation treatment and hormone supplementation after discharge, the patient’s condition was partially alleviated, and she was still being monitored at the six-month follow-up. (Fig. 4 ) VIDEO 1. Clip showing the removal of pituitary adenoma with basilar sinus extension. CS = cavernous sinus, ICA = internal carotid artery. © Tao Hong, published with permission. Click here to view. Discussion With the transformation of surgical treatment for PAs from microsurgical to endoscopic surgery, the EEA can serve as a mature technique for the removal of intrasellar PAs, which has evolved enormously through continuous technological progress over the years. [ 16 ] These findings have also gradually led us to use the EEA for PAs with multidirectional invasion, and the most common examples are the suprasellar region and the CS. The CS is located on both sides of the sellar region and communicates with numerous peripheral venous systems, accommodating many important neurovascular structures. Building on recent anatomical contributions describing the possibility of approaching the CS via the EEA, great progress has been made in the total resection rate of high Knosp grade PAs, and our team has recently reported 75.2% total tumor resection in 129 patients with Knosp grade 4 PAs. [ 2 , 6 ] However, there is still a type of tumor that is considered the most difficult to achieve complete resection during surgery, which is to invade other surrounding areas through the CS. Among them, it is well-known that PAs within the CS extend through the oculomotor cistern and paraclinoid space, which has been reported in surgical anatomy and clinical cases. [ 4 , 7 ] Besides, as the venous drainage channel of the CS, the basilar sinus could also constitute the weak point of PA extension. Till now, except for the symptoms of PAs, there is no characteristic clinical presentation of basilar sinus extension that helps skull base surgeons distinguish this particular subset of PAs, which often leads to intraoperative residue and postoperative recurrence. The main reason for this is the inadequate understanding of basilar sinus extension, which has been mistakenly thought to originate from the PA with clival invasion and further invade the periosteal layer after completing bone destruction, as described in our previous study. [ 10 ] When we first encounter this type of PA, after seeing the posterior boundary of the CS during the operation, we mistakenly believe that the PA has reached the tumor boundary and stopped the operation. However, through postoperative review, it was found that there were still significant residual tumors in the basilar sinus. Therefore, we conducted a systematic retrospective analysis using imaging data and surgical videos and found that this type of tumor is different from common pituitary macroadenoma, where long-term compression leads to thinning or even disappearance of the bony structure in the dorsum sellae. In this case, basilar sinus extension would be much rarer, and we speculate that this is because prolonged posterior compression by intrasellar PAs can lead to a reduction or even loss of space in the basilar sinus. At this time, PAs with posterior extension are more likely to break through the double-layered dura mater behind the dorsum sellae and extend to the prepontine cistern. In recent reports, Xu et al. [ 1 ] and Yang et al. [ 17 ] reported on the growth pattern of PAs breaking through the posterior wall of the CS and further subdivided it into the cerebral peduncle and Dorello's canal extension. We also encountered patients in whom the tumor within the posterior area of the CS was removed and immediately entered the intracranial space, with obvious CSF leakage, which is clearly inconsistent with our description of basilar sinus extension. Through the exploration of epoxy sheet plastination, we further recognized the PA extension corridor between the CS and the basilar sinus from the perspective of sectional anatomy and proposed that the “triangular” sign can be used as a typical imaging manifestation. Based on the surgical procedure, a series of anatomical markers have been discovered in endoscopic endonasal anatomical research to assist surgeons in locating corridors for PA extension. On this basis, we believe that the safest surgical strategy is tumor resection, which should be completed through combined transclival and transcavernous sinus approaches. In their analysis of venous drainage from the basilar sinus, Mizutani et al. reported that the emissary veins in the clivus connect to the basilar sinus and are more often located in the middle clivus. [ 18 ] Tucci et al. showed that there is direct communication between the basilar sinus and diploic vein in the clivus, especially near the midline clivus and at the junction of the occipital and sphenoid bones, where there are more connections. [ 19 ] The basilar sinus is also related to the anterior condylar vein, anterior internal vertebral venous plexus, anterior external vertebral venous plexus, and marginal sinus at its caudal end. [ 20 ] Therefore, to reduce postoperative recurrence and increase the endocrine relief rate, the safest surgical strategy is to remove the bone with tumor infiltration in the midline clivus simultaneously, which also reflects the advantages of the EEA and should be the preferred treatment option. While extension of the PA into the basilar sinus is less common than extension into the basilar sinus, intraoperative interference with the sixth cranial nerve can easily lead to postoperative eye movement disorders. Previous literature suggests that the interdural segment of the abducens nerve is at great risk when clivus resection extends transversely, so we should pay close attention to the abducens nerve during the process of interdural PA resection to avoid injury. [ 6 ] With these imaging, anatomical and surgical experiences, in subsequent intraoperative applications, we usually remove the tumor along the natural growth pathway in the CS and then drill part of the bone with tumor infiltration in the clivus to the basilar sinus for total resection of the tumor according to intraoperative neuronavigation localization, with satisfactory results. Limitations In brief, this study has several limitations: (1) the area that can be involved in basilar sinus for PA extension could not be determined with respect to the current study; and (2) the procedure needed to be performed by experienced skull base surgeons; thus, the applicability of these results to surgeons with lower patient volume may be limited. Conclusions The basilar sinus can serve as a potential breakthrough route through the CS compartments for PA invasion. Special attention should be given to the "triangle” sign in preoperative sagittal imaging, especially for Grade Knosp4 PAs. The transclival corridor provided by the EEA is ideal for accessing tumors in the basilar sinus and removing bony structures in the midline clivus. With a clear understanding of the invasion corridor for this subset of PAs and corresponding surgical techniques, PAs with basilar sinus extension can be safely removed without increasing the risk of surgery. Declarations Presentation： None. Assistance with the study: We express our sincere appreciation to Dr. Bo Wen Wu for the illustration. Competing Interests: All authors disclose non-financial interests that are directly or indirectly related to the work submitted for publication. Provenance and peer review Not commissioned, externally peer-reviewed. Sources of funding: This work was supported by the National Natural Science Foundation of China (grant Manuscript (Excluding all author details and affiliations) nos.82201271), the Jiangxi Provincial Natural Science Foundation (grant nos. 20232BAB216057), Jiangxi Provincial Training program for academic and technical leaders in major disciplines (20243BCE51146). Conflict of interest disclosure: The author declares no conflict of interest Ethical Approval This study was authorized by the Ethics Committee of the First Affiliated Hospital of Consent to Publish declaration : Not applicable. Author Contribution Xiao Wu: Conceptualization, Data curation, Investigation, Writing – original draft, Writing – review & editing, Funding acquisition, ResourcesLi Min Xiao: Writing – original draft, Writing – review & editingHaoyang Peng: Writing – original draftShi Zhou Xing: ConceptualizationLiang liang: Writing – review & editingPeng Wang: ConceptualizationBowen Wu: Conceptualization, VisualizationLaisheng Pan: ConceptualizationZhiqiang Liu: ConceptualizationTao Hong: Conceptualization, Writing – review & editingHan ding: Conceptualization, Writing – original draft, Writing – review & editingShenhao Xie: ConceptualizationJie Wu: ConceptualizationJie Zhan: ConceptualizationBin Tang: ConceptualizationAll authors reviewed the results and approved the final version of the manuscript. Data Availability The data that support the findings of this study are available from the corresponding author upon reasonable request. References Xu Y, Mohyeldin A, Asmaro KP et al (2022) Intracranial Breakthrough Through Cavernous Sinus Compartments: Anatomic Study and Implications for Pituitary Adenoma Surgery. Oper Neurosurg (Hagerstown) 23(2):115–124. 10.1227/ons.0000000000000291 Xiao L, Ouyang T, Wu B et al (2023) Subclassification of Knosp Grade 4 Pituitary Adenoma: Bringing Insights Into the Significance of Tumor Growth Pathways. Neurosurgery 92(1):213–222. 10.1227/neu.0000000000002197 Knosp E, Steiner E, Kitz K, Matula C (1993) Pituitary adenomas with invasion of the cavernous sinus space: a magnetic resonance imaging classification compared with surgical findings. Neurosurgery 33(4):610–618. 10.1227/00006123-199310000-00008 Ferrareze Nunes C, Lieber S, Truong HQ et al (2018) Endoscopic endonasal transoculomotor triangle approach for adenomas invading the parapeduncular space: surgical anatomy, technical nuances, and case series. J Neurosurg 130(4):1304–1314 Published 2018 Apr 13. 10.3171/2017.10.JNS17779 Yang Y, Bao Y, Xie S et al (2021) Identification of the Extradural and Intradural Extension of Pituitary Adenomas to the Suprasellar Region: Classification, Surgical Strategies, and Outcomes. Front Oncol. ;11:723513. Published 2021 Jul 20. 10.3389/fonc.2021.723513 Ding H, Wu X, Wu BW et al (2024) Further investigation of the lateral approach for the resection of Knosp grade 4 pituitary adenomas in endoscopic endonasal surgery. J Neurosurg 141(1):184–194 Published 2024 Feb 16. 10.3171/2023.12.JNS23922 Xu Y, Nunez MA, Mohyeldin A et al (2022) Microsurgical anatomy of the dorsal clinoidal space: implications for endoscopic endonasal parasellar surgery. J Neurosurg 137(5):1418–1430 Published 2022 Feb 4. 10.3171/2021.12.JNS211974 Kawase T, van Loveren H, Keller JT, Tew JM (1996) Meningeal architecture of the cavernous sinus: clinical and surgical implications. Neurosurgery 39(3):527–536. 10.1097/00006123-199609000-00019 Wu X, Ding H, Yang L et al (2021) Invasive Corridor of Clivus Extension in Pituitary Adenoma: Bony Anatomic Consideration, Surgical Outcome and Technical Nuances. Front Oncol 11:689943 Published 2021 Jun 25. 10.3389/fonc.2021.689943 Wu X, Xie SH, Tang B et al (2021) Pituitary adenoma with posterior area invasion of cavernous sinus: surgical anatomy, approach, and outcomes. Neurosurg Rev 44(4):2229–2237. 10.1007/s10143-020-01404-1 Yang Y, Bao Y, Xie S et al (2021) Identification of the Extradural and Intradural Extension of Pituitary Adenomas to the Suprasellar Region: Classification, Surgical Strategies, and Outcomes. Front Oncol. ;11:723513. Published 2021 Jul 20. 10.3389/fonc.2021.723513 Ouyang T, Zhang N, Xie S et al (2021) Outcomes and Complications of Aggressive Resection Strategy for Pituitary Adenomas in Knosp Grade 4 With Transsphenoidal Endoscopy. Front Oncol 11:693063 Published 2021 Jun 21. 10.3389/fonc.2021.693063 Beck-Peccoz P, Lania A, Beckers A, Chatterjee K, Wemeau JL (2013) 2013 European thyroid association guidelines for thediagnosis and treatment of thyrotropin-secreting pituitary tumors. Eur Thyroid J 2(2):76–82 Melmed S, Bronstein MD, Chanson P et al (2018) A Consensus Statement on acromegaly therapeutic outcomes. Nat Rev Endocrinol 14(9):552–561 Nieman LK, Biller BM, Findling JW et al (2015) Treatment of Cushing’s syndrome: an Endocrine Society Clinical Practice Guideline. J Clin Endocrinol Metab 100(8):2807–2831 Ueberschaer M, Katzendobler S, Biczok A et al (2022) A simple surgical technique for sellar closure after transsphenoidal resection of pituitary adenomas in the context of risk factors for cerebrospinal fluid leaks and meningitis. Neurosurg Focus 53(6):E7. 10.3171/2022.9.FOCUS22225 Yang F, Bi Y, Zhou Q et al (2023) Pituitary adenoma with cavernous sinus compartment penetration and intracranial extension: surgical anatomy, approach, and outcomes. Front Oncol. ;13:1169224. Published 2023 May 18. 10.3389/fonc.2023.1169224 Mizutani K, Toda M, Kurasawa J et al (2017) Analysis of the venous channel within the clivus using multidetector computed tomography digital subtraction venography. Neuroradiology 59(3):213–219. 10.1007/s00234-017-1784-4 Tucci M, Chaiyamoon A, Suwannakhan A et al (2023) A Novel Direct Pathway of Dural Venous Outflow from the Basilar Venous Plexus via the Diploic Space of the Clivus. World Neurosurg 175:e1182–e1185. 10.1016/j.wneu.2023.04.093 Mizutani K, Akiyama T, Yoshida K, Toda M (2018) Skull Base Venous Anatomy Associated with Endoscopic Skull Base Neurosurgery: A Literature Review. World Neurosurg 120:405–414. 10.1016/j.wneu.2018.09.067 Additional Declarations No competing interests reported. Supplementary Files video.mp4 Cite Share Download PDF Status: Published Journal Publication published 03 Oct, 2025 Read the published version in Neurosurgical Review → Version 1 posted Editorial decision: Revision requested 28 May, 2025 Reviews received at journal 28 May, 2025 Reviews received at journal 26 May, 2025 Reviews received at journal 22 May, 2025 Reviews received at journal 21 May, 2025 Reviewers agreed at journal 18 May, 2025 Reviewers agreed at journal 16 May, 2025 Reviewers agreed at journal 15 May, 2025 Reviewers agreed at journal 15 May, 2025 Reviewers invited by journal 15 May, 2025 Editor assigned by journal 15 May, 2025 Submission checks completed at journal 15 May, 2025 First submitted to journal 10 May, 2025 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-6634932","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":458263187,"identity":"7c1e9acd-775e-47de-9265-ec0d40e2ee75","order_by":0,"name":"Xiao Wu+","email":"","orcid":"","institution":"Department of Neurosurgery, The First Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang, China","correspondingAuthor":false,"prefix":"","firstName":"Xiao","middleName":"","lastName":"Wu+","suffix":""},{"id":458263188,"identity":"1c3d6295-c332-4a91-8f40-5888c27fb1e0","order_by":1,"name":"Li Min Xiao","email":"","orcid":"","institution":"Jiangxi Cancer Hospital","correspondingAuthor":false,"prefix":"","firstName":"Li","middleName":"Min","lastName":"Xiao","suffix":""},{"id":458263189,"identity":"8c0951ca-003c-47fc-92e8-e94aeee5313c","order_by":2,"name":"HaoYang Peng","email":"","orcid":"","institution":"The First Clinical Medical College, Nanchang University","correspondingAuthor":false,"prefix":"","firstName":"HaoYang","middleName":"","lastName":"Peng","suffix":""},{"id":458263190,"identity":"6a45218e-2519-4fc4-8ecb-56bb496086ab","order_by":3,"name":"Shi Zhou Xing","email":"","orcid":"","institution":"Department of Neurosurgery, The First Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang, China","correspondingAuthor":false,"prefix":"","firstName":"Shi","middleName":"Zhou","lastName":"Xing","suffix":""},{"id":458263191,"identity":"f7189a80-8d20-47c6-bbf7-5cc47235731a","order_by":4,"name":"Peng Wang","email":"","orcid":"","institution":"Department of Neurosurgery, The First Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang, China","correspondingAuthor":false,"prefix":"","firstName":"Peng","middleName":"","lastName":"Wang","suffix":""},{"id":458263192,"identity":"4c23f270-08e0-42b2-9682-2ef208aa5dad","order_by":5,"name":"Liang Liang","email":"","orcid":"","institution":"Anhui Medical University","correspondingAuthor":false,"prefix":"","firstName":"Liang","middleName":"","lastName":"Liang","suffix":""},{"id":458263193,"identity":"2072c506-e65c-4997-acfc-b516ded592ca","order_by":6,"name":"Bo Wen Wu","email":"","orcid":"","institution":"Department of Neurosurgery, The First Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang, China","correspondingAuthor":false,"prefix":"","firstName":"Bo","middleName":"Wen","lastName":"Wu","suffix":""},{"id":458263194,"identity":"517fb3ef-ae57-4c7e-94ec-18ac4466e4a3","order_by":7,"name":"Lai Sheng Pan","email":"","orcid":"","institution":"Department of Neurosurgery, The First Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang, China","correspondingAuthor":false,"prefix":"","firstName":"Lai","middleName":"Sheng","lastName":"Pan","suffix":""},{"id":458263195,"identity":"bd51ba18-abda-47c2-a0bd-2af30d598270","order_by":8,"name":"Zhi Qiang Liu","email":"","orcid":"","institution":"Department of Neurosurgery, The First Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang, China","correspondingAuthor":false,"prefix":"","firstName":"Zhi","middleName":"Qiang","lastName":"Liu","suffix":""},{"id":458263196,"identity":"197368db-873e-4398-82a1-16a74df9c006","order_by":9,"name":"Shen Hao Xie","email":"","orcid":"","institution":"Department of Neurosurgery, The First Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang, China","correspondingAuthor":false,"prefix":"","firstName":"Shen","middleName":"Hao","lastName":"Xie","suffix":""},{"id":458263197,"identity":"1cdc1c25-2f59-46cf-8f9b-4c82a5a3bb59","order_by":10,"name":"Jie Wu","email":"","orcid":"","institution":"Department of Neurosurgery, The First Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang, China","correspondingAuthor":false,"prefix":"","firstName":"Jie","middleName":"","lastName":"Wu","suffix":""},{"id":458263198,"identity":"ec03846f-1ecf-4ec9-a76e-b69f435aa723","order_by":11,"name":"Jie Zhan","email":"","orcid":"","institution":"Department of Radiology, The First Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang, China","correspondingAuthor":false,"prefix":"","firstName":"Jie","middleName":"","lastName":"Zhan","suffix":""},{"id":458263199,"identity":"ae13e567-a041-499d-b779-6a04d1b81c7a","order_by":12,"name":"Bin Tang","email":"","orcid":"","institution":"Department of Neurosurgery, The First Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang, China","correspondingAuthor":false,"prefix":"","firstName":"Bin","middleName":"","lastName":"Tang","suffix":""},{"id":458263200,"identity":"9f15f4ba-8f91-4807-a881-771f3ba688a3","order_by":13,"name":"Han Ding","email":"","orcid":"","institution":"Department of Neurosurgery, Jiangxi Provincial People's Hospital, The First Affiliated Hospital of Nanchang Medical College, Nanchang，China","correspondingAuthor":false,"prefix":"","firstName":"Han","middleName":"","lastName":"Ding","suffix":""},{"id":458263201,"identity":"368fe0c2-80c6-4264-b7cc-9f0b039a532b","order_by":14,"name":"Tao Hong","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA00lEQVRIiWNgGAWjYBACAwbmAwcSDGwY2EC8BKK0sLElPvhQkUaSFh5jwxlnDpPgMHP5BjNp3rbziX3SDcwfHu6wY+Bv78ZvmWUbQxpQy+3ENpkDbBKJZ5IZJM6c3YDfYccYjoG0GLNJJLAxJLYxMxhI5BLSwtgG1HIOpIX5Q2JbPTFamJmB3j8gB9TCIJHYdpgYLWmMwEBOlmOTOdgG1HKch7BfDp//AIxKOx752c2HP/5sq5bjb+/FrwUBJBgbQBQPkcrBWkhQOwpGwSgYBSMLAACAMkSwHU+OQgAAAABJRU5ErkJggg==","orcid":"","institution":"Department of Neurosurgery, The First Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang, China","correspondingAuthor":true,"prefix":"","firstName":"Tao","middleName":"","lastName":"Hong","suffix":""}],"badges":[],"createdAt":"2025-05-10 13:08:12","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-6634932/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-6634932/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1007/s10143-025-03816-3","type":"published","date":"2025-10-03T15:58:08+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":83146172,"identity":"62ceed85-72f3-4993-8f74-81762042b2e3","added_by":"auto","created_at":"2025-05-20 13:02:03","extension":"jpeg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":1523896,"visible":true,"origin":"","legend":"\u003cp\u003eAnatomy of the cavernous sinus (CS)-basilar sinus corridor. A: The anterior wall of the left CS and bony structure covering the clivus were removed, and the CS-basilar sinus corridor was exposed. B: The communication area between the CS and the basilar sinus located in the superomedial space of the gulfar segment abducens nerve, which contains the meningohypophyseal trunk and its branches. C: Local magnification after removal of the CS segment of the internal carotid artery. D: Artistic illustration demonstrating the corridor of the pituitary adenoma (PA) with basilar sinus extension in the endoscopic endonasal view. E: Artistic illustration demonstrating the \"triangle” sign (white triangle) in sagittal views.\u003c/p\u003e","description":"","filename":"floatimage1.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-6634932/v1/c5f4cc668c216c9da5b540b3.jpeg"},{"id":83147152,"identity":"e9cd3cec-342f-43d1-b061-ece086d01901","added_by":"auto","created_at":"2025-05-20 13:10:03","extension":"jpeg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":628249,"visible":true,"origin":"","legend":"\u003cp\u003eA-B\u003cstrong\u003e: \u003c/strong\u003eThe CS-basilar sinus corridor was observed by epoxy sheet plastination in axial and sagittal views. C: An artificial illustration demonstrating the corridor of the PA with basilar sinus extension in the transcranial view.\u003c/p\u003e","description":"","filename":"floatimage2.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-6634932/v1/aa1ed8add4652e7fe9be5f8d.jpeg"},{"id":83148686,"identity":"d31d02a8-8b78-4db3-aab4-c0d98d2c1f4f","added_by":"auto","created_at":"2025-05-20 13:26:03","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":1794388,"visible":true,"origin":"","legend":"\u003cp\u003eA 31-year-old female with PA recurrence 3 years after the first endoscopic endonasal surgery. A-B Preoperative MR image of the first surgery showing the patient’s normal pituitary on the right side and the tumor with CS and basilar sinus invasion (white triangle) on the left side. C: Postoperative MR image showing that the intrasellar and CS tumors were completely removed, but the basilar sinus corridor was ignored because it was not recognized at the time. D: Three years later, MRI reexamination revealed that the “triangle” sign (white triangle) had reached the middle clivus at a size of approximately 3.2 × 1.8 × 2.3 cm. E: The tumor was exposed through drilling the bony structure covering the clivus. F: \u0026nbsp;The tumor was removed through the transclival approach. G: Final resection cavity was exposed after resecting the tumor within the CS and basilar sinus. H: The process of skull base reconstruction of cavernous sinus and basilar sinus after surgery. I: Postoperative imaging demonstrated that the tumor was completely removed.\u003c/p\u003e","description":"","filename":"floatimage3.png","url":"https://assets-eu.researchsquare.com/files/rs-6634932/v1/0fd547a1ff5764e8314aa53e.png"},{"id":83147464,"identity":"075a5575-9549-41d0-95b6-8b84d040fd0c","added_by":"auto","created_at":"2025-05-20 13:18:03","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":1872714,"visible":true,"origin":"","legend":"\u003cp\u003eA 25-year-old female with headache and dizziness for 1 month. A: Preoperative sagittal MR image showing that the “triangle” sign (white triangle) had reached the inferior clivus. B: Preoperative CT revealed intact bone on the surface of the clivus, with a posterior space-occupying lesion connecting the CS. C: After the transpterygoid approach was used to expose the paraclival ICA and the bony surface of the clivus and anterior wall of the CS were removed, the PAs were completely exposed. D: The CS-basilar sinus corridor was observed behind the posterior genu of the CS segment internal carotid artery. E: Final resection cavity was exposed after resecting the tumor within the CS and basilar sinus. F: Postoperative imaging demonstrated that the tumor within the basilar sinus was completely removed.\u003c/p\u003e","description":"","filename":"floatimage4.png","url":"https://assets-eu.researchsquare.com/files/rs-6634932/v1/796b4bcd52c2578b9afb7673.png"},{"id":92883894,"identity":"a1846662-f627-454a-8b59-f51a5f3950ee","added_by":"auto","created_at":"2025-10-06 16:10:31","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":7060477,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6634932/v1/5ff3315e-e1a0-421a-b49f-95942b668104.pdf"},{"id":83146189,"identity":"7b3d2d24-893d-484d-b86b-89da13bcc806","added_by":"auto","created_at":"2025-05-20 13:02:03","extension":"mp4","order_by":6,"title":"","display":"","copyAsset":false,"role":"supplement","size":21231114,"visible":true,"origin":"","legend":"","description":"","filename":"video.mp4","url":"https://assets-eu.researchsquare.com/files/rs-6634932/v1/1bc11aa7b50c0a5b60800243.mp4"}],"financialInterests":"No competing interests reported.","formattedTitle":"Pituitary Adenoma Extended to the Basilar Sinus: Lessons from Anatomical and Radiological Study（An Experimental Research）","fulltext":[{"header":"Highlights","content":"\u003cp\u003e1.Special attention should be given to the \"triangle\u0026rdquo; sign in preoperative sagittal imaging, especially for Grade Knosp4 PAs.\u003c/p\u003e\u003cp\u003e2.The basilar sinus can serve as a potential breakthrough route through the cavernous sinus compartments for PA invasion.\u003c/p\u003e"},{"header":"Introduction","content":"\u003cp\u003eTreatment strategies for pituitary adenoma (PA) need to consider many aspects, which promotes the development of clinical and anatomical research. Previous studies have confirmed that PAs can invade surrounding structures through various anatomical weak points, and these types of tumors are often referred to as invasive PAs by scholars.1 The variety of invasive modalities makes surgical treatment difficult, even for experienced skull base surgeons. One of the most challenging types is PA with cavernous sinus (CS) invasion, which is also the focus of numerous clinical reports.\u003csup\u003e[\u003cspan additionalcitationids=\"CR2 CR3 CR4 CR5\" citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e–\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]\u003c/sup\u003e\u003c/p\u003e \u003cp\u003eHowever, it is still believed that a small subset of PAs can further extend to other locations through the CS, such as the paraclinoid and parapeduncular spaces, which would cause certain challenges to the total resection of tumors.\u003csup\u003e[\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]\u003c/sup\u003e As Kawase et al.\u003csup\u003e[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]\u003c/sup\u003e and Xu et al.\u003csup\u003e[\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]\u003c/sup\u003e showed, the meningeal structure within the CS has several weak points, providing a potential route for tumor extension. In contrast to the looseness and thinness of the medial wall of the CS or oculomotor cistern, the basilar sinus, as a normal venous drainage channel, can also become a weak point in the CS, leading to further extension of the PAs. Nevertheless, PAs with basilar sinus extension may be overlooked in many patients with coexisting predominant CS, clivus and suprasellar extension, leading to intraoperative residual tumor and postoperative recurrence. Whether this subset of PAs has characteristic imaging manifestations is an issue that deserves further exploration.\u003c/p\u003e \u003cp\u003eWe previously conducted in-depth research on PAs with multiple corridor invasion, such as the CS, clivus, and diaphragma sellae.\u003csup\u003e[\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan additionalcitationids=\"CR10 CR11\" citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e–\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]\u003c/sup\u003e The aim of the present study was to highlight the basilar sinus corridor and related surgical strategies for PA extension through anatomical research and clinical case studies, which have not been described previously. This particular subset of PAs has implications for the total resection rate, symptom relief, and postoperative recurrence for endoscopic endonasal surgery.\u003c/p\u003e "},{"header":"Method","content":"\u003ch3\u003eAnatomical Study\u003c/h3\u003e\u003cp\u003eThis study was authorized by the Ethics Committee of e First Affiliated Hospital of Nanchang University. Four cadaver head specimens were used for epoxy sheet plastination to elaborate the CS-basilar sinus corridor in axial and sagittal sections. Five colored silicon–injected human head specimens were used for endoscopic endonasal dissection. The anatomical process of endoscopic endonasal approach (EEA) with a 4 mm diameter × 18 cm length endoscope (Karl Storz, 0° and 30°). The bilateral endoscopic endonasal transpterygoid and transclival approaches were used to expose the basilar sinus and lateral compartment of the CS to simulate the operation process.\u003c/p\u003e\u003ch2\u003ePatient Selection and Analyses\u003c/h2\u003e\u003cp\u003eThe clinical and radiological database was examined to identify PA patients who received EEA treatment from July 2017 to June 2023. Among these patients, we screened PAs with basilar sinus extension that met our inclusion criteria. The inclusion criteria were as follows: 1) basilar sinus extension without bone destruction in the dorsum sellae based on preoperative imaging and intraoperative evaluation; 2) complete preoperative and postoperative imaging data and postoperative follow-up data; and 3) postoperative pathology confirming that the tumor was PA.\u003c/p\u003e\u003cp\u003ePreoperative clinical data, including sex, age, clinical manifestations, and endocrine and ophthalmic examination results, were obtained from medical records. All patients underwent routine T1- and T2-weighted imaging and T1-weighted 3D MP-RAGE sequencing before and after the operation (Siemens, Erlangen, Germany). The Knosp grade and subclassification were used to evaluate cavernous sinus invasion.\u003csup\u003e[\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]\u003c/sup\u003e\u003c/p\u003e\u003ch3\u003ePostoperative evaluation\u003c/h3\u003e\u003cp\u003eThe postoperative evaluation included reexamination imaging, histopathological findings, ophthalmic examination results and complications. The time from resection to the last call was defined as the follow-up time in this study. To narrow the differences among evaluators, the extent of tumor resection was determined by an individual neuroradiologist and experienced neurosurgeons through preoperative and postoperative enhanced MRI. The resection range was determined by postoperative MRI. Gross total resection (GTR) was defined as no residual tumor. Subtotal resection(STR)was defined as a resection range ≥ 80%. Partial resection (PR) was defined as a resection range \u0026lt; 80%.\u003c/p\u003e\u003cp\u003eEndocrine remission was evaluated at 3 months postoperatively according to the guidelines from the latest consensus. \u003csup\u003e[\u003cspan additionalcitationids=\"CR14\" citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e–\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]\u003c/sup\u003e For prolactin (PRL)-secreting adenomas, serum PRL \u0026lt; 20 ng/mL in female patients or, \u0026lt; 15 ng/mL in male patients; for adrenocorticotropic hormone (ACTH)-secreting adenomas, a serum cortisol nadir of \u0026lt; 2 mg/dL or normal 24-hour urinary free cortisol test at 3 months; and for growth hormone (GH)-secreting tumors, normalization of serum insulin-like growth factor-1 level (IGF-1), basal serum GH \u0026lt; 2.5 ng/mL, or an oral glucose tolerance test of 0.4 ng/mL.\u003c/p\u003e"},{"header":"Results","content":"\u003cdiv id=\"Sec6\" class=\"Section2\"\u003e \u003ch2\u003eAnatomic Findings\u003c/h2\u003e \u003cp\u003eThe basilar sinus includes lateral interconnecting channels with the CS and connects the vertebral venous plexus downward and the inferior petrosal sinus laterally. The connection between the CS and the basilar sinus is located in the interdural space on the dorsal side of the clivus, behind the posterior genu of the CS segment of the ICA. In front is the periosteum layer of the clivus, and behind is the meningeal layer of the brainstem. It can also be considered the superensomedial space of the gulfar segment abducens nerve and beneath the petrosphenoidal ligament, which contains the meningohypophyseal trunk and its branches. (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e,\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e2\u003c/span\u003e)\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003ePatient Demographics\u003c/h3\u003e\n\u003cp\u003eA total of 881 patients were diagnosed with PA and underwent surgery during the study period and had pre- and postoperative images available for review. A total of 47 patients exhibited basilar sinus extension\u0026mdash;30 females and 17 males\u0026mdash;with an average age of 45.5 years. Eight patients with a history of previous surgery. The predominant presenting symptom observed was endocrine dysfunction (17 patients, 36.2%), including Cushing disease in 3 (6.4%) cases, prolactinomas in 2 (4.2%) cases, and acromegaly in 12 (25.5%) cases. Among these patients, prolactinomas choose surgery because of drug intolerance and obvious adverse reactions. Other symptoms included visual disturbance (16 patients, 34%), headache (12 patients, 25.5%) and cranial nerve palsy(3 patient, 6.4%). The overall maximum diameter could be divided into 16 (34%) case of macroadenomas and 31 (66%) case of giant adenomas. The mean tumor volume was 33.8cm\u0026sup3;. Based on the degree of CS invasion, 11 (23.4%) patients had Knosp grade 3 tumors, 10 (21.3%) had grade 4A tumors, 4 (8.5%) had grade 4B tumors, and 22 (46.8%) had grade 4AB tumors. There were 33 (70.2%) patients with Ki-67\u0026thinsp;\u0026ge;\u0026thinsp;3 and 14 (29.8%) patients with Ki-67\u0026thinsp;\u0026lt;\u0026thinsp;3. The total follow-up time ranged from 8 to 79 months, with an average of 41.6 months. (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eClinical characteristics of 47 PAs with basilar sinus extension\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"2\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eVariable\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eValue\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNo. of patients\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e47\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAge in yrs (range)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e45.5 (10\u0026ndash;69)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSex\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFemale (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e30 (63.8)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMale (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e17 (36.2)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTumor subtypes\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e3 (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e11 (23.4)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e4A (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e10 (21.3)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e4B (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e4 (8.5)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e4AB (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e22 (46.8)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePreop Sxs\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eVisual disturbance (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e16 (34.0)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eEndocrine dysfunction syndrome (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e17 (36.2)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHeadache (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e12 (25.5)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCN palsy\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCN III palsy (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2 (4.2)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCN VI palsy (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1 (2.1)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eIncidental finding (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3 (6.4)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTumor size\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMacroadenomas (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e16 (34.0)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGiant PAs (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e31 (66.0)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTumor volume\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e33.8cm\u0026sup3;\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNFA (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e30 (63.8)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFA (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e17 (36.2)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCushing disease (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3 (6.4)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eProlactinomas (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2 (4.2)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAcromegaly (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e12 (25.5)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePrevious surgery (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e8 (17.0)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eKi-67\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u0026ge;3 (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e33 (70.2)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u0026lt;3 (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e14 (29.8)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMean follow-up in mos (range)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e41.6 (8\u0026ndash;79)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"2\"\u003eFA\u0026thinsp;=\u0026thinsp;functional adenoma; NFA\u0026thinsp;=\u0026thinsp;nonfunctional adenoma; Sxs\u0026thinsp;=\u0026thinsp;symptoms.\u003c/td\u003e\u003c/tr\u003e \u003ctr\u003e\u003ctd colspan=\"2\"\u003eSubtypes of KG4PAs were evaluated according to the latest report.\u003csup\u003e2\u003c/sup\u003e\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003eImaging characteristics\u003c/h2\u003e \u003cp\u003eRadiographically, this tumor has a characteristic presentation and usually appears as a Knosp grade 4 PA with obvious extension in the lateral compartment of the CS. The PA extension is limited by the anterior periosteum layer in the clivus and posterior meningeal layer, forming a characteristic triangular structure(Figure \u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eE,\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e3\u003c/span\u003eD and \u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e4\u003c/span\u003eA). In addition, the high signal density of the basilar sinus was obliteration, and the \u0026ldquo;triangle\u0026rdquo; sign reached the lower clivus on T1-weighted imaging with gadolinium contrast enhancement in the sagittal section; however, there was no bony destruction of the clivus or dorsum sellae on the CT bone window. In detail, the three edges of the triangle symbol represent the clival surface, the posterior boundary of the tumor, and the connecting line between the superior surface of the dorsum sellae and the posterior boundary of the tumor.\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eSurgical techniques\u003c/h3\u003e\n\u003cp\u003eThe surgical procedures were performed under the protection of neuronavigation, intraoperative electrophysiological monitoring and Doppler measurements. Most of the patients were Knosp grade 4 with lateral compartment invasion of the CS, which was preoperatively judged via MRI and reaffirmed intraoperatively. As a result, a transpterygoid approach on the tumor side was needed to expose the lateral compartment of the CS and paraclival internal carotid artery (ICA) as the proximal control point. The surgical strategies and details for Knosp4 PAs have been described in our previous publications.\u003csup\u003e[\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]\u003c/sup\u003e\u003c/p\u003e \u003cp\u003eA special feature of this type of PA surgery is that the tumor in the CS is usually removed first until the area connecting to the basilar sinus is reached. To aid in the mobilization of the ICA, the meningohypophyseal trunk or inferior hypophyseal artery was cautiously coagulated and transected.\u003c/p\u003e \u003cp\u003ePA with basilar sinus extension hiding behind the clivus is considered a blind spot in endoscopic endonasal surgery. Therefore, for patients with \u0026ldquo;triangle\u0026rdquo; signs on preoperative imaging, the transclival approach was used to remove a portion of the bone in the clivus and the dorsum sellae, especially at the midline and the sphenoid occipital junction.\u003c/p\u003e \u003cp\u003eDue to the basilar sinus within the interdural space, the tumor can be found by opening the periosteal layer in the clivus. In these patients, there was less bleeding from the basilar sinus, and the tumor was relatively well identified. With the cooperation of neuronavigation and angle endoscopy, the tumor can be completely removed. At this point, bleeding from the basilar sinus increased, thus requiring compression hemostasis with fluid gelatin. The probability of intraoperative cerebrospinal fluid(CSF) leakage was low, owing to protection of the meningeal layer, and the skull base is reconstructed sequentially using the traditional method of autologous fat, T-frame, fibrin glue and nasal septum mucosal flap.\u003c/p\u003e\n\u003ch3\u003eSurgical outcomes\u003c/h3\u003e\n\u003cp\u003eIn this series, a comprehensive analysis revealed that 39 patients (83%) benefited from GTR, while the remaining 6 patients (12.8%) underwent STR and 2 patients (4.2%) underwent PR. During the last follow-up, the preoperative symptom of endocrine dysfunction improved in 15 patients (88.2%) to varying degrees. Other symptoms included visual disturbance, headache and cranial nerve palsy improved in 12 patients (75%), 8 patients (67.7%) and 2 patients (67.7%) respectively.\u003c/p\u003e \u003cp\u003eAfter surgery, 3 patients (6.4%) had transient cranial nerve palsy, 1 patient (2.1%) had permanent cranial nerve palsy, and another 1 patient (2.1%) had CSF leakage. No patient experienced lethal ICA injury. (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eSurgical results and postoperative complications in 47 patients\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eVariable\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eTotal (47)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eNFAs (30)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eFAs (17)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eExtent of resection\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGTR (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e39 (83.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e24 (80.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e15 (88.2)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSTR (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e6 (12.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4 (13.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2 (11.8)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePTR (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2 (4.2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2(6.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eResolution of preop Sxs\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eVisual disturbance (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e16 (34.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e11 (36.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e5 (29.4)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNo change (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e4 (25.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3 (27.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1 (20)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eImproved (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e12 (75.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e8 (72.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e4 (80)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHeadache (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e12 (25.5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e8 (26.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e4 (23.5)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNo change (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e4 (33.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2 (25.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2 (50.0)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eImproved (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e8 (67.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e6 (75.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2 (50.0)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCN palsy (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3 (6.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2 (6.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1 (5.9)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNo change (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1 (33.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1 (100)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eImproved (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2 (67.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2 (100)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eEndocrine remission\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eYes (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e15 (88.2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e15 (88.2)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNo (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2 (11.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2 (11.8)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePostop complications\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTransient CN palsy (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3 (6.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2 (6.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1 (5.9)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCN III\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1 (2.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1 (3.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCN VI\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2 (4.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1 (3.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1 (5.9)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePermanent CN palsy (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1 (2.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1 (3.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCN III\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCN VI\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1 (2.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1 (3.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCSF leakage (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1 (2.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1(5.9)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eICA injury (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cdiv id=\"Sec11\" class=\"Section2\"\u003e \u003ch2\u003eIllustrative Cases\u003c/h2\u003e \u003cdiv id=\"Sec12\" class=\"Section3\"\u003e \u003ch2\u003ePatient 1\u003c/h2\u003e \u003cp\u003eA 31-year-old female with PA was admitted to the hospital for tumor recurrence 3 years after the first endoscopic endonasal surgery. Ophthalmic examination revealed that the patient\u0026rsquo;s binocular vision decreased. On the MRI of the first surgery, the patient had a normal pituitary on the right side and a tumor with CS invasion on the left side. The patient underwent EEA to remove intrasellar and CS tumors, but the basilar sinus corridor was ignored because it was not recognized at the time. Multiple postoperative follow-up visits revealed that the tumor in the basilar sinus gradually increased, and radiotherapy or reoperation was recommended. However, the patient chose to continue the observation because of her lack of symptoms and fertility requirements. Three years later, MRI reexamination revealed that the \u0026ldquo;triangle\u0026rdquo; sign had reached the middle clivus, which was approximately 3.2 \u0026times; 1.8 \u0026times; 2.3 cm in size. During the operation, we completely removed the tumor through the transclival approach. Postoperative imaging demonstrated that the tumor was completely removed, and there were no significant complications. (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e3\u003c/span\u003e)\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv id=\"Sec13\" class=\"Section2\"\u003e \u003ch2\u003ePatient 2\u003c/h2\u003e \u003cp\u003eA 25-year-old female with headache and dizziness for 1 month. She had two previous PA surgical histories through the EEA due to acromegaly and postoperative pathological confirmation of growth hormone adenoma. Ophthalmic examination showed no obvious decline in vision or visual field. Preoperative sagittal MRI showed that the \u0026ldquo;triangle\u0026rdquo; sign had reached the inferior clivus. Axial MR image showing an irregular density shadow in the right CS and an incased ICA, measuring approximately 3.5 \u0026times; 1.6 \u0026times; 1.8 cm. Preoperative CT revealed intact bone on the surface of the clivus, with a posterior space-occupying lesion connecting the CS. The patient underwent endoscopic endonasal surgery. After the transpterygoid approach was used to expose the paraclival ICA and the bony surface of the clivus and anterior wall of the CS were removed, the PAs were completely exposed. At this time, the PAs in the CS were removed first, after which the tumor was exposed by opening the periosteal layer on the clival surface. There was no CSF leakage after the tumor within the basilar sinus was completely removed. The patient's left eyeball abduction was limited, and her pituitary function decreased postoperatively. Through rehabilitation treatment and hormone supplementation after discharge, the patient\u0026rsquo;s condition was partially alleviated, and she was still being monitored at the six-month follow-up. (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e4\u003c/span\u003e)\u003c/p\u003e \u003cp\u003eVIDEO 1. Clip showing the removal of pituitary adenoma with basilar sinus extension. CS\u0026thinsp;=\u0026thinsp;cavernous sinus, ICA\u0026thinsp;=\u0026thinsp;internal carotid artery. \u0026copy; Tao Hong, published with permission. Click here to view.\u003c/p\u003e \u003c/div\u003e"},{"header":"Discussion","content":"\u003cp\u003eWith the transformation of surgical treatment for PAs from microsurgical to endoscopic surgery, the EEA can serve as a mature technique for the removal of intrasellar PAs, which has evolved enormously through continuous technological progress over the years.\u003csup\u003e[\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]\u003c/sup\u003e These findings have also gradually led us to use the EEA for PAs with multidirectional invasion, and the most common examples are the suprasellar region and the CS.\u003c/p\u003e \u003cp\u003eThe CS is located on both sides of the sellar region and communicates with numerous peripheral venous systems, accommodating many important neurovascular structures. Building on recent anatomical contributions describing the possibility of approaching the CS via the EEA, great progress has been made in the total resection rate of high Knosp grade PAs, and our team has recently reported 75.2% total tumor resection in 129 patients with Knosp grade 4 PAs.\u003csup\u003e[\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]\u003c/sup\u003e\u003c/p\u003e \u003cp\u003eHowever, there is still a type of tumor that is considered the most difficult to achieve complete resection during surgery, which is to invade other surrounding areas through the CS. Among them, it is well-known that PAs within the CS extend through the oculomotor cistern and paraclinoid space, which has been reported in surgical anatomy and clinical cases.\u003csup\u003e[\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]\u003c/sup\u003e Besides, as the venous drainage channel of the CS, the basilar sinus could also constitute the weak point of PA extension.\u003c/p\u003e \u003cp\u003eTill now, except for the symptoms of PAs, there is no characteristic clinical presentation of basilar sinus extension that helps skull base surgeons distinguish this particular subset of PAs, which often leads to intraoperative residue and postoperative recurrence. The main reason for this is the inadequate understanding of basilar sinus extension, which has been mistakenly thought to originate from the PA with clival invasion and further invade the periosteal layer after completing bone destruction, as described in our previous study.\u003csup\u003e[\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]\u003c/sup\u003e\u003c/p\u003e \u003cp\u003eWhen we first encounter this type of PA, after seeing the posterior boundary of the CS during the operation, we mistakenly believe that the PA has reached the tumor boundary and stopped the operation. However, through postoperative review, it was found that there were still significant residual tumors in the basilar sinus.\u003c/p\u003e \u003cp\u003eTherefore, we conducted a systematic retrospective analysis using imaging data and surgical videos and found that this type of tumor is different from common pituitary macroadenoma, where long-term compression leads to thinning or even disappearance of the bony structure in the dorsum sellae. In this case, basilar sinus extension would be much rarer, and we speculate that this is because prolonged posterior compression by intrasellar PAs can lead to a reduction or even loss of space in the basilar sinus. At this time, PAs with posterior extension are more likely to break through the double-layered dura mater behind the dorsum sellae and extend to the prepontine cistern.\u003c/p\u003e \u003cp\u003eIn recent reports, Xu et al.\u003csup\u003e[\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]\u003c/sup\u003e and Yang et al.\u003csup\u003e[\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]\u003c/sup\u003e reported on the growth pattern of PAs breaking through the posterior wall of the CS and further subdivided it into the cerebral peduncle and Dorello's canal extension. We also encountered patients in whom the tumor within the posterior area of the CS was removed and immediately entered the intracranial space, with obvious CSF leakage, which is clearly inconsistent with our description of basilar sinus extension.\u003c/p\u003e \u003cp\u003eThrough the exploration of epoxy sheet plastination, we further recognized the PA extension corridor between the CS and the basilar sinus from the perspective of sectional anatomy and proposed that the \u0026ldquo;triangular\u0026rdquo; sign can be used as a typical imaging manifestation. Based on the surgical procedure, a series of anatomical markers have been discovered in endoscopic endonasal anatomical research to assist surgeons in locating corridors for PA extension. On this basis, we believe that the safest surgical strategy is tumor resection, which should be completed through combined transclival and transcavernous sinus approaches.\u003c/p\u003e \u003cp\u003eIn their analysis of venous drainage from the basilar sinus, Mizutani et al. reported that the emissary veins in the clivus connect to the basilar sinus and are more often located in the middle clivus.\u003csup\u003e[\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]\u003c/sup\u003e Tucci et al. showed that there is direct communication between the basilar sinus and diploic vein in the clivus, especially near the midline clivus and at the junction of the occipital and sphenoid bones, where there are more connections.\u003csup\u003e[\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]\u003c/sup\u003e The basilar sinus is also related to the anterior condylar vein, anterior internal vertebral venous plexus, anterior external vertebral venous plexus, and marginal sinus at its caudal end.\u003csup\u003e[\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]\u003c/sup\u003e Therefore, to reduce postoperative recurrence and increase the endocrine relief rate, the safest surgical strategy is to remove the bone with tumor infiltration in the midline clivus simultaneously, which also reflects the advantages of the EEA and should be the preferred treatment option.\u003c/p\u003e \u003cp\u003eWhile extension of the PA into the basilar sinus is less common than extension into the basilar sinus, intraoperative interference with the sixth cranial nerve can easily lead to postoperative eye movement disorders. Previous literature suggests that the interdural segment of the abducens nerve is at great risk when clivus resection extends transversely, so we should pay close attention to the abducens nerve during the process of interdural PA resection to avoid injury.\u003csup\u003e[\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]\u003c/sup\u003e\u003c/p\u003e \u003cp\u003eWith these imaging, anatomical and surgical experiences, in subsequent intraoperative applications, we usually remove the tumor along the natural growth pathway in the CS and then drill part of the bone with tumor infiltration in the clivus to the basilar sinus for total resection of the tumor according to intraoperative neuronavigation localization, with satisfactory results.\u003c/p\u003e \u003cp\u003eLimitations\u003c/p\u003e \u003cp\u003eIn brief, this study has several limitations: (1) the area that can be involved in basilar sinus for PA extension could not be determined with respect to the current study; and (2) the procedure needed to be performed by experienced skull base surgeons; thus, the applicability of these results to surgeons with lower patient volume may be limited.\u003c/p\u003e"},{"header":"Conclusions","content":"\u003cp\u003eThe basilar sinus can serve as a potential breakthrough route through the CS compartments for PA invasion. Special attention should be given to the \"triangle\u0026rdquo; sign in preoperative sagittal imaging, especially for Grade Knosp4 PAs. The transclival corridor provided by the EEA is ideal for accessing tumors in the basilar sinus and removing bony structures in the midline clivus. With a clear understanding of the invasion corridor for this subset of PAs and corresponding surgical techniques, PAs with basilar sinus extension can be safely removed without increasing the risk of surgery.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003ePresentation：\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNone.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAssistance with the study:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWe express our sincere appreciation to Dr. Bo Wen Wu for the illustration.\u003c/p\u003e\n\u003ch2\u003eCompeting Interests:\u003c/h2\u003e\n\u003cp\u003eAll authors disclose non-financial interests that are directly or indirectly related to the work submitted for publication.\u003c/p\u003e\n\u003ch2\u003eProvenance and peer review\u003c/h2\u003e\n\u003cp\u003eNot commissioned, externally peer-reviewed.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eSources of funding:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis work was supported by the National Natural Science Foundation of China (grant Manuscript (Excluding all author details and affiliations) nos.82201271), the Jiangxi Provincial Natural Science Foundation (grant nos. 20232BAB216057), Jiangxi Provincial Training program for academic and technical leaders in major disciplines (20243BCE51146).\u003c/p\u003e\n\u003ch2\u003eConflict of interest disclosure:\u003c/h2\u003e\n\u003cp\u003eThe author declares no conflict of interest\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthical Approval\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis study was authorized by the Ethics Committee of the First Affiliated Hospital of\u003c/p\u003e\n\u003ch2\u003eConsent to Publish declaration\u003c/strong\u003e:\u003c/h2\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e\n\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\n\u003cp\u003eXiao Wu: Conceptualization, Data curation, Investigation, Writing \u0026ndash; original draft, Writing \u0026ndash; review \u0026amp; editing, Funding acquisition, ResourcesLi Min Xiao: Writing \u0026ndash; original draft, Writing \u0026ndash; review \u0026amp; editingHaoyang Peng: Writing \u0026ndash; original draftShi Zhou Xing: ConceptualizationLiang liang: Writing \u0026ndash; review \u0026amp; editingPeng Wang: ConceptualizationBowen Wu: Conceptualization, VisualizationLaisheng Pan: ConceptualizationZhiqiang Liu: ConceptualizationTao Hong: Conceptualization, Writing \u0026ndash; review \u0026amp; editingHan ding: Conceptualization, Writing \u0026ndash; original draft, Writing \u0026ndash; review \u0026amp; editingShenhao Xie: ConceptualizationJie Wu: ConceptualizationJie Zhan: ConceptualizationBin Tang: ConceptualizationAll authors reviewed the results and approved the final version of the manuscript.\u003c/p\u003e\n\u003ch2\u003eData Availability\u003c/h2\u003e\n\u003cp\u003eThe data that support the findings of this study are available from the corresponding author upon reasonable request.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eXu Y, Mohyeldin A, Asmaro KP et al (2022) Intracranial Breakthrough Through Cavernous Sinus Compartments: Anatomic Study and Implications for Pituitary Adenoma Surgery. Oper Neurosurg (Hagerstown) 23(2):115\u0026ndash;124. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1227/ons.0000000000000291\u003c/span\u003e\u003cspan address=\"10.1227/ons.0000000000000291\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eXiao L, Ouyang T, Wu B et al (2023) Subclassification of Knosp Grade 4 Pituitary Adenoma: Bringing Insights Into the Significance of Tumor Growth Pathways. Neurosurgery 92(1):213\u0026ndash;222. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1227/neu.0000000000002197\u003c/span\u003e\u003cspan address=\"10.1227/neu.0000000000002197\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKnosp E, Steiner E, Kitz K, Matula C (1993) Pituitary adenomas with invasion of the cavernous sinus space: a magnetic resonance imaging classification compared with surgical findings. Neurosurgery 33(4):610\u0026ndash;618. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1227/00006123-199310000-00008\u003c/span\u003e\u003cspan address=\"10.1227/00006123-199310000-00008\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eFerrareze Nunes C, Lieber S, Truong HQ et al (2018) Endoscopic endonasal transoculomotor triangle approach for adenomas invading the parapeduncular space: surgical anatomy, technical nuances, and case series. J Neurosurg 130(4):1304\u0026ndash;1314 Published 2018 Apr 13. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.3171/2017.10.JNS17779\u003c/span\u003e\u003cspan address=\"10.3171/2017.10.JNS17779\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eYang Y, Bao Y, Xie S et al (2021) Identification of the Extradural and Intradural Extension of Pituitary Adenomas to the Suprasellar Region: Classification, Surgical Strategies, and Outcomes. Front Oncol. ;11:723513. Published 2021 Jul 20. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.3389/fonc.2021.723513\u003c/span\u003e\u003cspan address=\"10.3389/fonc.2021.723513\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eDing H, Wu X, Wu BW et al (2024) Further investigation of the lateral approach for the resection of Knosp grade 4 pituitary adenomas in endoscopic endonasal surgery. J Neurosurg 141(1):184\u0026ndash;194 Published 2024 Feb 16. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.3171/2023.12.JNS23922\u003c/span\u003e\u003cspan address=\"10.3171/2023.12.JNS23922\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eXu Y, Nunez MA, Mohyeldin A et al (2022) Microsurgical anatomy of the dorsal clinoidal space: implications for endoscopic endonasal parasellar surgery. J Neurosurg 137(5):1418\u0026ndash;1430 Published 2022 Feb 4. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.3171/2021.12.JNS211974\u003c/span\u003e\u003cspan address=\"10.3171/2021.12.JNS211974\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKawase T, van Loveren H, Keller JT, Tew JM (1996) Meningeal architecture of the cavernous sinus: clinical and surgical implications. Neurosurgery 39(3):527\u0026ndash;536. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1097/00006123-199609000-00019\u003c/span\u003e\u003cspan address=\"10.1097/00006123-199609000-00019\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWu X, Ding H, Yang L et al (2021) Invasive Corridor of Clivus Extension in Pituitary Adenoma: Bony Anatomic Consideration, Surgical Outcome and Technical Nuances. Front Oncol 11:689943 Published 2021 Jun 25. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.3389/fonc.2021.689943\u003c/span\u003e\u003cspan address=\"10.3389/fonc.2021.689943\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWu X, Xie SH, Tang B et al (2021) Pituitary adenoma with posterior area invasion of cavernous sinus: surgical anatomy, approach, and outcomes. Neurosurg Rev 44(4):2229\u0026ndash;2237. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1007/s10143-020-01404-1\u003c/span\u003e\u003cspan address=\"10.1007/s10143-020-01404-1\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eYang Y, Bao Y, Xie S et al (2021) Identification of the Extradural and Intradural Extension of Pituitary Adenomas to the Suprasellar Region: Classification, Surgical Strategies, and Outcomes. Front Oncol. ;11:723513. Published 2021 Jul 20. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.3389/fonc.2021.723513\u003c/span\u003e\u003cspan address=\"10.3389/fonc.2021.723513\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eOuyang T, Zhang N, Xie S et al (2021) Outcomes and Complications of Aggressive Resection Strategy for Pituitary Adenomas in Knosp Grade 4 With Transsphenoidal Endoscopy. Front Oncol 11:693063 Published 2021 Jun 21. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.3389/fonc.2021.693063\u003c/span\u003e\u003cspan address=\"10.3389/fonc.2021.693063\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBeck-Peccoz P, Lania A, Beckers A, Chatterjee K, Wemeau JL (2013) 2013 European thyroid association guidelines for thediagnosis and treatment of thyrotropin-secreting pituitary tumors. Eur Thyroid J 2(2):76\u0026ndash;82\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMelmed S, Bronstein MD, Chanson P et al (2018) A Consensus Statement on acromegaly therapeutic outcomes. Nat Rev Endocrinol 14(9):552\u0026ndash;561\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eNieman LK, Biller BM, Findling JW et al (2015) Treatment of Cushing\u0026rsquo;s syndrome: an Endocrine Society Clinical Practice Guideline. J Clin Endocrinol Metab 100(8):2807\u0026ndash;2831\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eUeberschaer M, Katzendobler S, Biczok A et al (2022) A simple surgical technique for sellar closure after transsphenoidal resection of pituitary adenomas in the context of risk factors for cerebrospinal fluid leaks and meningitis. Neurosurg Focus 53(6):E7. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.3171/2022.9.FOCUS22225\u003c/span\u003e\u003cspan address=\"10.3171/2022.9.FOCUS22225\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eYang F, Bi Y, Zhou Q et al (2023) Pituitary adenoma with cavernous sinus compartment penetration and intracranial extension: surgical anatomy, approach, and outcomes. Front Oncol. ;13:1169224. Published 2023 May 18. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.3389/fonc.2023.1169224\u003c/span\u003e\u003cspan address=\"10.3389/fonc.2023.1169224\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMizutani K, Toda M, Kurasawa J et al (2017) Analysis of the venous channel within the clivus using multidetector computed tomography digital subtraction venography. Neuroradiology 59(3):213\u0026ndash;219. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1007/s00234-017-1784-4\u003c/span\u003e\u003cspan address=\"10.1007/s00234-017-1784-4\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eTucci M, Chaiyamoon A, Suwannakhan A et al (2023) A Novel Direct Pathway of Dural Venous Outflow from the Basilar Venous Plexus via the Diploic Space of the Clivus. World Neurosurg 175:e1182\u0026ndash;e1185. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.wneu.2023.04.093\u003c/span\u003e\u003cspan address=\"10.1016/j.wneu.2023.04.093\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMizutani K, Akiyama T, Yoshida K, Toda M (2018) Skull Base Venous Anatomy Associated with Endoscopic Skull Base Neurosurgery: A Literature Review. World Neurosurg 120:405\u0026ndash;414. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.wneu.2018.09.067\u003c/span\u003e\u003cspan address=\"10.1016/j.wneu.2018.09.067\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"neurosurgical-review","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"nrev","sideBox":"Learn more about [Neurosurgical Review](https://www.springer.com/journal/10143)","snPcode":"10143","submissionUrl":"https://submission.nature.com/new-submission/10143/3","title":"Neurosurgical Review","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"basilar sinus, epoxy sheet plastination, pituitary adenoma, cavernous sinus, endoscopic endonasal approach","lastPublishedDoi":"10.21203/rs.3.rs-6634932/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6634932/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cdiv id=\"ASec1\" class=\"AbstractSection\"\u003e \u003cdiv class=\"Heading\"\u003ePurpose\u003c/div\u003e \u003cp\u003ePituitary adenoma (PA) with basilar sinus extension has been neglected in previous literature. In this study, 47 cases of such a subset of PAs were introduced, and the surgery-related anatomy and strategies were discussed.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"ASec2\" class=\"AbstractSection\"\u003e \u003cdiv class=\"Heading\"\u003eMethods\u003c/div\u003e \u003cp\u003eThe medical records of patients with basilar sinus extension were analyzed retrospectively. Four human head specimens were used for epoxy sheet plastination, and five were used for endoscopic endonasal dissection.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"ASec3\" class=\"AbstractSection\"\u003e \u003cdiv class=\"Heading\"\u003eResults\u003c/div\u003e \u003cp\u003eThe connection between the cavernous sinus (CS) and the basilar sinus is located in the superomedial space of the gulfar segment abducens nerve and beneath the petrosphenoidal ligament. The characteristic manifestation on enhanced sagittal MR images is the \u0026ldquo;triangle\u0026rdquo; sign, which means that the high signal in the basilar sinus disappears and is replaced by triangular-like tumor protrusions without destruction of the clivus or dorsum sellae. The most common symptom was endocrine dysfunction (17 patients; 36.2%), with 88.2% of patients experiencing remission postoperatively. According to the dataset, 83% of patients achieved total resection through the endoscopic endonasal approach. Abducens nerve palsy (3 patients, 6.4%) were the most common postoperative complications, but two patients were alleviated during postoperative follow-up.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"ASec4\" class=\"AbstractSection\"\u003e \u003cdiv class=\"Heading\"\u003eConclusion\u003c/div\u003e \u003cp\u003eThe basilar sinus can serve as a potential breakthrough path through the CS compartments for PA invasion. With a clear anatomical understanding of the invasion corridor for this subset of PAs and corresponding surgical techniques, PAs can be safely removed without increasing surgical risk.\u003c/p\u003e \u003c/div\u003e","manuscriptTitle":"Pituitary Adenoma Extended to the Basilar Sinus: Lessons from Anatomical and Radiological Study（An Experimental Research）","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-05-20 13:01:58","doi":"10.21203/rs.3.rs-6634932/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-05-28T21:39:38+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-05-28T14:47:28+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-05-26T19:46:34+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-05-22T10:13:07+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-05-22T00:40:52+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"31148705837953267785095481738842969253","date":"2025-05-18T15:20:31+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"167394068700314602022515166914322914570","date":"2025-05-16T20:29:10+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"14860537026463927227205555229639722131","date":"2025-05-15T23:27:00+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"11100269697883204495478581789833960949","date":"2025-05-15T16:57:07+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-05-15T16:47:59+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-05-15T16:46:46+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-05-15T16:09:09+00:00","index":"","fulltext":""},{"type":"submitted","content":"Neurosurgical Review","date":"2025-05-10T12:55:59+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"neurosurgical-review","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"nrev","sideBox":"Learn more about [Neurosurgical Review](https://www.springer.com/journal/10143)","snPcode":"10143","submissionUrl":"https://submission.nature.com/new-submission/10143/3","title":"Neurosurgical Review","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"5ea1abcf-9aaa-4462-87d9-d537280a2f6a","owner":[],"postedDate":"May 20th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2025-10-06T16:04:15+00:00","versionOfRecord":{"articleIdentity":"rs-6634932","link":"https://doi.org/10.1007/s10143-025-03816-3","journal":{"identity":"neurosurgical-review","isVorOnly":false,"title":"Neurosurgical Review"},"publishedOn":"2025-10-03 15:58:08","publishedOnDateReadable":"October 3rd, 2025"},"versionCreatedAt":"2025-05-20 13:01:58","video":"","vorDoi":"10.1007/s10143-025-03816-3","vorDoiUrl":"https://doi.org/10.1007/s10143-025-03816-3","workflowStages":[]},"version":"v1","identity":"rs-6634932","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6634932","identity":"rs-6634932","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}